Mobile phone backlighting is one of the largest application markets for LEDs today. As the market is already saturated, the price decline is obvious. Although the sales volume continues to increase, the sales amount has not grown significantly. Despite this, the backlighting application of 5 to 10 mobile phone devices will continue to be a new driving force for the market.
This article refers to the address: http://
The following exclusive interview with Adobe Magazine, Director of Application Engineering at AnalogicTech, discusses the power management design needs for LED backlighting.
What is the application method for a TFT LCD screen with a size of 5 to 10 inches?
David Brown: TFT LCD screens are available in a variety of applications, including high-end smartphones, small portable multimedia players (PMPs such as the small DVD player typically 5 to 9 inches), handheld portable navigation devices (PNDs), Notebook computers, small notebooks, tablet computers, handheld video games and e-book readers.
What is the difference in power management requirements for these applications?
David Brown: The power management needs of these various applications are very different, and each specific device design structure has its own unique needs. For each device, the designer must consider the battery type, screen size, and number of backlight LEDs used. After understanding the system requirements, we must also weigh the structure of the LED driver circuit, as well as the cost and complexity of the device, to achieve a balance. All of the above factors are sufficient to determine the best way to drive a backlight LED on a portable device.
The LED backlight structure is mainly divided into two types, a single series series power supply or a plurality of series serial/parallel power sources. Although a single series of series power supplies uses a lower constant current, the input power supply must be boosted to meet the total forward voltage level of the series power supply to drive the LEDs. Conversely, multiple sets of series/parallel LED power supplies require a higher constant current to drive, but reduce the need for high voltages. The difference in boost converter requirements depends on cost, complexity, and energy conversion efficiency (for the user, the battery life between charge cycles). Ultimately, the best solution will be determined based on the product's product characteristics, size and performance requirements.
What are the technical challenges in power management for small-size backlit screens?
David Brown: There are indeed many challenges. The first challenge is related to the discussion mentioned in the first part. Designers must balance the system requirements, power sources, and circuit architecture to select the appropriate LED driver circuit structure. Therefore, the designer must weigh the available budget based on the final product.
In addition, size and height also create another technical limitation. Charged pumps with high switching frequency and inductive DC/DC boost solutions allow for the use of smaller external components. In particular, the LED driver circuit based on the charge pump, because the charge pump and the parallel LED power supply require only a small external capacitor, the parallel LED power supply is used to reduce the size of the external components. Whether it is to reduce the size of the external components of the charge pump or the inductive solution, the most important consideration is the switching frequency of the LED driver circuit.
For example, smart phones are usually thinner, lighter, and less expensive because they require smaller components. In contrast, notebook computers are cheaper and bulkier, and have enough room to accommodate larger components.
Will the mainstream of high-end mobile phones in the future be AMOLED?
David Brown: AMOLEDs are an unstoppable trend in small handheld devices, as these devices excel in all possible applications regardless of resolution and color reproduction. However, due to cost considerations and the lack of suppliers in the market, the current adoption of AMOLED as the mainstream of displays has slowed down. In addition, if the AMOLED panel is larger than 5 inches, the installation cost is usually too expensive for most portable products.
There are a few devices on the market that use AMOLEDs, and the display sizes of such products fall between 3 and 5 inches. In the future, as the number of manufacturers increases and the cost of displays decreases, I think AMOLED displays will become the mainstream of mobile applications. AnalogicTech has also supported this market and is actively researching power management solutions for this display technology.
FBT Splitter utilizes precision technology to combine or distribute light from single/multiple inputs to single/multiple outputs bi-directionally. They are designed for power splitting and tapping in telecommunication equipment, CATV network, and test equipment.Available Splitter FBT counts are 1x2 and 2x2 in split ratios of: 50/50, 40/60, 30/70, 20/80, 10/90, 5/95, 1/99, 60/40, 70/30, 80/20, 90/10, 95/5, and so on.Single and dual window Fiber Splitter are available with 900µm loose tube singlemode fiber or 250µm bare fiber and terminated or unterminated as per your needs. Unconnectorized FBT splitters come with no connectors for easy splicing or connectorization. Connectorized FBT splitters are available with your choice of Fiber Optic Connectors.Foclink,a reliable supplier of fiber FBT splitter is always beside u 7*24.
FBT Splitter
FBT Splitter,Splitter FBT,Small FBT Splitter
Foclink Co., Ltd , http://www.scfiberpigtail.com